Element Suppresion

Here's some info on the suppression of elements by USSPACECOM:
NEWS AND COMMENT by Dave Ransom
mailto:rans7500@spacelink.nasa.gov
[Reposted from the RPV Astronomy BBS @ (520) 282-5559]
31 MAR 99 Reliable sources inform me that USSPACECOM would like to
change the orbital model used for all TLEs and do NOT plan
to release the code for their new "Special Perturbations"
model. Since the "General Perturbations" model, SGP4/SDP4,
is used in STSPLUS and most other satellite tracking programs,
such a change would render that software all but useless
except for historical purposes. I'll continue to track the
situation and post Bulletins on my RPV BBS and FLASH.TXT on
my Home Page as I learn more.
23 MAR 99 My sources report that USSPACECOM has completed suppressing
TLEs from their "hit list" and that no more TLEs should be
doing a disappearing act. My contact continues "... there is
now a feeling of paranoia in releasing anything for operating
DOD satellites, even the Navstars which are used for civilian
purposes". I fear the GPS TLEs are gone for good ...
22 MAR 99 I have received unofficial confirmation that the suppression
of GPS and DMSP TLEs at NASA/GSFC Orbital Information Group
is the result of a policy change at US Space Command. I (and
others) view this as a most unfortunate precedent. Not only
is it a stupid decision -- more accurate orbital data for the
GPS satellites can be obtained with a GPS receiver -- but it
denies unclassified data to satellite users and the general
public, data which is paid for by the American taxpayer. GPS
and DMSP TLEs are suppressed now, what next?
This policy change should not be allowed to stand unchallenged.
I suggest that satellite users and those interested in satellite
tracking write to Congress demanding that it be reversed. It may
even take the Freedom of Information Act to apply some real
pressure on USSPACECOM. Those individuals in the SeeSat-L forum
are welcome to repeat my comments.
19 MAR 99 GSFC/OIG has deleted all trace of GPS satellites from their
on-line database accessible to registered users. This appears
to be a permanent policy change from USSPACECOM, unfortunately.
I have implemented new TLE processing software which checks
the age of TLEs posted in my TLEnnn.ZIP, GSFCnnn.ZIP and
TLyymmdd.ZIP files. TLEs are deleted which are more than 21
to 60 days old as a function of Mean Motion; LEO satellites
are dropped at 21 days and GEO satellites at 60 days with
other orbits falling in between those two limits.
The GSFC/OIG TLEs for today were processed with the new
software and quite a few TLEs were dropped, some dating back
as far as 1968! I hardly think TLEs of that age are of much
value to anyone. Comments invited.
16 MAR 99 USSPACECOM has apparently decided to discontinue distributing
current TLEs for all GPS satellites and a number of other
satellites. GSFC/OIG reports "No elements available" and TS
Kelso's current data includes TLEs that are at least 10 days
old. Unless the situation is corrected, I will stop including
these TLEs in the data I distribute rather than continue to
post outdated data.
There has been no explanation for this change in policy. I
fail to understand the rationale behind it since the basic
orbital data for GPS satellites are included in the data that
is transmitted to GPS receivers continuously. Any skilled
"potential adversary" could easily obtain the data. Only the
rest of us are denied the information.
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